Breech-closure for guns.



K. A. BRUNING.

BRBEGH GLOSURE FOB. GUNS.

APPLICATION FILED JULY 16, 1912.

Patented June 23,1914.

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Vi/'nesses K. A. BR'UNING.

BREEGH GLOSURE POR GUNS.

APPLICATION FILED JUBY 16, 1912.

1,101,1 16, Patented Jun 23, 1914.

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KARL AUGUST BRUNING, OF HERSTLAL, BELGIUM.

BREECH-CLOSURE FOR GUNS.

Specication of Letters Patent.

Patented June 23, 1914.

Application filed July 16, 1912. Serial No. 709,812.

To all whom it may concern Be it known that I, KARL AUGUST BRU- NING, a subject of the Emperor of Germany, and resident of Herstal, in the Kingdom of Belgium, have invented certain new and useful Improvements in Breech-Closures for Guns; and I do hereby declare the following to be a full, clear, and exact description of the invention7 such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or figures of reference marked therein, which form a part of this specification.

The present invention relates to a breech closure for automatic guns in which the locking is produced by a change in the inclination of the bolt, this change taking place at the end of the forward movement; during this change of inclination ribs carried by the bolt come opposite stops on the breech casing to effect the locking` of the breech.

The invention is differentiated from I known devices of the kind by the manner in which the unlocking is produced upon tiring. It is the recoil of the cart-ridge which, acting eccentrically relatively to the bolt, produces a vertical movement of the rear end of the latter in such a manner as to disengage the ribs formed thereon from the stops of the breech casing. v

The firing pin is guided in an invariable manner and rectilinearly. The locking is therefore produced in reality by a change of inclination between the axis of the liring pin and that of the bolt.

In the construction illustrated, the firing pin and the bolt haveJ their axes parallel throughout the entire period of the opening movement of the bolt, the bolt inclining relatively to the firing pin when locked.

The drawings illustrate a constructional embodiment of the invention, in which r- Figure 1 is a longitudinal section of the breech casing, the bolt occupying the locking position and being represented in elevation. Fig. 2 is a similar section, but in this case all the parts are represented in section. Fig. 3 is a cross-section along A B of Fig. 1 and of Fig. 2 (viewed from the front). Fig. 4 is a cross-section along E F in Figs. 1 and 2 (viewed from the front). Fig. 5 is a cross-section along C D in Figs. 1 and 2 (viewed from the rear). Fig. 6 is a longitudinal section, similar to Fig. `1,'but with the bolt unlocked. along G H of Fig. 6 (viewed from the front) Fig. 8 is a partial section of another constructional form of bolt.

In Figs. 1 and 6 the hammer member and the trigger elements have not been represented.

The bolt 1 is formed on each of its lateral faces in front with a rib 2 and at the rear with two ribs 3 and t, the ribs, 2 and 3 being located in a plane parallel to the top of the bolt.

The bolt is hollowed longitudinally, forming a cavity 5 which serves for the reception of the percussion or firing pin. Each of the inner lateral faces of this housing is formed with an oblique groove or channel 6.

The front face 7 of the bolt is as shown perpendicular to its aXis and the arrangement is such that when the bolt is closed and locked its front face inclines downwardly and forwardly relatively to the plane of the barrel, and that when the gun is fired the rear end of the bolt rises and its front face becomes vertical relatively to the plane of the barrel.

The lower face of the cavity 5 presents at its rear a shoulder 31 terminating in an inclined surface 32.

At its rear, the bolt presents a projection 33 which at its rear is inclined rearwardly and downwardly and is acted upon by a rod 34: terminating in a conical portion. This rod has a tendency to move forward under the inliuence of a helical spring 35. r1`he bolt and its spring are housed in a cylindrical passage 36 in the breech casing. When the bolt moves rearward, the projection 33 slides in the slot 37 connecting the passage 36 with the breech casing proper. The rod 34 therefore constantly tends to move thebolt forward and also acts in such a manner as to depress the rear portion of the bolt. The `spring 35 acts as a storing means.

The breech casing 8 iixed to the barrel 9 presents laterally upon each of its vertical walls two longitudinal grooves 10 and 11 corresponding with the ribs on the bolt. The grooves 10 correspond with the ribs 1 and the lgrooves 11 with the ribs 2 and 3.

Fig. 7 is a cross-section Y These grooves are connected onev with the A other upon either side of the axis by two vertical grooves 12 extending throughout the entire height of the breech casingtsee Fig. 4).

The breech casing is formed with an ejection aperture 52 in one of its sides.

The firing pin 13 is carried by a member 14 housed in the cavity 5 in the bolt.

The carrier of the firing pin presents at itsr upper part upon each side a longitudinalV rib 15 which engages a corresponding groove 16 in the breech casing 8, so as to constitute a guiding means, and at 17 it carries lateral cylindrical projections corresponding with the slots 6 in the bolt. j

The firng-pin-car'rier presents at its lower portion a semi-cylindrical housing for the reception of the ring pin 13, which is held in place by a flange 24 integral with the carrier. with easy friction in the carrier. Its movement in either direction is limited by a lug or projection 25 on one of its faces, which works in an elongated recess in the under side of the ringpin 'carrier between shoulders 48 and 49. The firing pin comprises at its rear a heel-piece 26 extended laterally upon either side by reinforcements 27 adapted to be actuated by the hammer member 28. The rear face of this heel-piece presents at its lower part an inclined surface 29, the purpose o-f which is hereinafter described.

The point 30 of the firing pin passes through the front wall of the bolt.

The carrier 14 presents in front at its upper part a recess 18 in which is engaged a project-ion 19 of the cover slide 20 serving for operating the mechanism by hand. This slide 2O is guided on each side by a longitudinal rib 21 sliding in 'a groove 22 in the breech casing. On either side at its rear the slide 20 carries projections 23 the outer .face of which is roughened (Fig. y7) these projections afford a hold for the marksmans hand when loading the firearm.

The hammer member 28 pivoted at 38 in the frame is moved forward by a plunger 39 which is pivoted at 40 to the hammer member and in connection with the trigger 42 and acted upon by a spring 41. The. hammer member 28 presents a solid portion 51 and is prolonged on either side of the portion of the breech casing containing the passage 36 by two cheeks 50 which act upon the lateral reinforcements 27 of the firing pin. The action of the trigger 42 and the 'maintenance of the hammer member in its cocked position are effected in any convenient known manner.

The operation of this firearm is as follows: Wrhen the parts occupy4 the position represented in Figs. 1 and 2, the charge of powder in exploding forces back the car-- tridge 43. This acts at 44 eccentrically to the `axis of the bolt (see Fig. 2). The bolt is blocked at the front by the ribs 2. At the The firing pin 13 therefore slides the horizontal grooves 10 and 11 in l'they breech casing (see Figs. 6 and 7)'. During this movement of the bolt the face 32 thereof acts upon the surface 29 of the heel-piece of the firing-pin and causes the latter to recede. The walls of the oblique slots 6 simultaneously `act upon theV projections 17 of the iiring-pin-carrier and also displace the latter rearwardly. The bolt being then re- Y leased recedes, carrying with it the firingpin and its carrier, the firingepm causing the hammcrmember to rotate. around its Y pivot whereby the hammer member is cocked. When the recoil is completely absorbed, the spring 35A again presses the bolt forward into the position represented in Fig. 6. The ribs being then situated in the vertical grooves 12, the eccentric action ofV the spring 35 upon the bolt then `causes the latter to pivot downward until it occupies the position represented in Fig. 1. During this pivoting, yunder the influence of its projections 17 the ring-pin-carrier reoccupies the position represented in Fig. 2, the firingpin being free in the carrier. The action upon the trigger 42 releases the hammer member which by means of its cheeks 5() acts upon the reinforcements 27 of the firing-pin and produces firing. The operation continues in this manner until the magazine has been emptied.

In ord-er to load the firearm at the commencement of firing, without the automatic action of the cartridge, the projections 23 of the slide 2O are acted upon. This slide acts by its projection 19 upon the ringepincarrier which by the intermediary of the projections 17 and the walls of the slots 6 lifts the bolt into the unlocked position.

It should be noted that owing to t-he small amount of 'the leverage about the points 44 and 46, the cartridge exerting a pressure horizontally vat the point 44 and the tilting of the bolt being effected `about the point 46 and to the inverse action of the spring 35 which tends to depress the bolt, the tilting movement of the bolt due to t-he recoil of t-he cartridge necessitates considerabley force and that unlocking does not take place until after a relatively long time, in such a manner that a complete closing of the barrelV is maintained during the first period of firing. These effects can be regulated'by varying the profile of the front face of the bolt as specially represented in Fig. 8. By imparting' an appropriate profile to this face, it is possible to modify the -action of the lever arm 44-46 as desired. Thus Fig. 8 represents the front face of the bolt 1 and the cartridge 43 which -acts upon the point 44 of the front face of the bolt.

IVhat I claim is:

1. An automatic firearm comprising in combination, a tiring-pin movable invariably in a rectilinear direction; a breech casing formed with grooves and stops; a recoil operated breech bolt formed with ribs which are normally in engagement with said stops but which, upon the tilting of said breech bolt about its forward end resulting from the recoil, engage with said grooves and permit of the rearward movement of said breech bolt and firing-pin and the unlocking of the breech; means to return the said movable elements into their original forward position; and guiding means for said breech bolt and firing-pin.

2. In an automatic firearm, the combination of a breech casing having a groove and stop; a iiring-pin movable invariably in a rectilinear direction; a recoil-operated breech bolt having its axis inclined to that of the firing-pin when locked in firing position and parallel therewith when unlocked; a rib on the breech bolt which is in engagement with said stop during the locking period, but which upon tilting of said bolt by the recoil after firing, comes into engagement with said groove topermit the rearward movement of said breech bolt and said firing-pin which is-carried along thereby, and consequently the unlocking o-f the breech; means for returning the breech bolt and firing-pin into their original forward position; and means for guiding said two elements in their rearward and forward movements.

3. In an automatic firearm, the combination of a cartridge shell; trigger mechanism; a breech casing having a plurality of grooves and stops; a firing-pin; means to guide said pin invariably in a rectilinear direction; a breech bolt adapted to be tilted by the recoil of the cart-ridge shell to change the inclination of the axis of the bolt relatively to that of the firing-pin; a plurality of ribs on said bolt adapted normally to encounter said stops to lock the bolt, but to engage in said grooves upon the said cha-nge of inclination, to permit the rearward movement of said breech bolt and firing-pin as a unit to set the firing mechanism; springactuated means to return said bolt and pin into their original forwardpositions to relock the breech; and means to guide said bolt and pin in their forward and rearward movements.

Il. An automatic firearm comprising a rectilinearly movable firing-pin; a breech casing formed with grooves and stops; a breech bolt opera-tively engaging said pin and formed with front ribs adapted to prevent vertical movement of the bolt and rear ribs adapted to encounter said stops, when the breech is closed; a cartridge shell adapted -to recoil against the front face of the breech bolt to tilt said bolt about the said front ribs so as to cause said rear ribs to engage in said grooves and to permit the rearward movement of said bolt and firing pin as a unit; guiding means for said two movable elements; and means to return said elements into their original forward positions.

5. An automatic firearm comprising a firing-pin; a breech casing formed with stops and also with horizontal grooves connected by vertical grooves; a breech bolt formed with front ribs adapted to prevent vertical movement of the bolt and rear ribs adapted to encounter said stops, when the breech is closed; a cartridge shell adapted to recoil on the breech bolt to tilt said bolt about its front ribs so as to cause said rear ribs to move upwardly along said vertical grooves and then to register with said horizontal grooves and thus to permit the rearward movement of breech bolt and firing-pin as a unit; a spring-actuated rod adapted to act upon the rear end of the breech bolt to cause said bolt to reoccupy it-s original position with the rear ribs thereof in engagement with the stops of the breech casing; and means to guide said breech bolt and firing-pin in their reciprocatory movements.

6. An automatic breech-operated firearm comprising a firing-pin; a iring-pin-carrier; projections on the carrier; a breech casing formed with grooves and stops; a breech bolt formed with slots engaged by said projections, and a plurality of ribs adapted to engage said stops when the breech is closed, said breech bolt being caused by the recoil action to tilt so as to change the inclination of its axis and to effect the registration of said ribs with said grooves and thus tc permit the rearward movement of said firingpin and iring-pin-carrier along with the breech bolt; means for guiding the said three movable elements; and means for returning themto their original positions.

In testimony whereof I aliix my signature in presence of two witnesses.

KARL AUGUST BRAUNING. lVitnesses:

LEONARD LEVER, GEORGES VANDER HUEYHEN.

Copies of this patent may be obtained for ve cents each, by addressing the Commissioner of Patents, Washington, D. C. 

